Mechanisms of nitrate removal and antimicrobial action of Fe–Cu@GA-AC nanocomposite - A comparison of RSM and SVM-Monte Carlo optimization

Abstract

Globally, nitrate contamination in groundwater represents a paramount environmental concern, bearing notable ecological and health ramifications. This research scrutinized the efficacy of a groundbreaking nanocomposite—engineered with Iron (Fe), Arabic Gum (GA), and Copper (Cu) supported on activated carbon (Fe–Cu@GA-AC) —in nitrate removal and its potential antimicrobial capabilities from spent coffee grounds post-extraction. The nanocomposite's operation is rooted in two mechanisms: adsorption and photodegradation. An extensive investigation was undertaken on various parameters, such as the nitrate's initial concentration, the nanocomposite's dose, the pH, and the duration of contact. Characterization techniques confirmed the nanocomposite's synthesis, exhibiting properties aligned with anticipated specifications. Through the utilization of Response Surface Methodology (RSM) and cutting-edge machine learning algorithms, optimal conditions were identified for maximal nitrate removal: a dose of 2 g/L, a concentration of 60 mg/L, a contact time of 48.76 min, and a pH value of 9. Analogous optimal conditions were also observed in the Support Vector Machine-Monte Carlo Simulation (SVM-MCs) algorithm. This framework identified the dose as the most influential factor for removal process efficiency. Moreover, the nanocomposite inhibited gram-positive and gram-negative bacteria, with the most significant inhibition detected in Staphylococcus aureus (S.aureus). Furthermore, the introduction of Benzoquinone (BQ) and (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO) resulted in a notable reduction in nitrate degradation, highlighting the pivotal role of hydroxyl radicals and conduction band electrons. This novel nanocomposite offers prospects in environmental remediation, water treatment, and antimicrobial uses, paving the way for future research.